The present invention relates to a variable damping force shock absorber.
Variable damping force shock absorbers are well known. Japanese Utility Model First (unexamined Publication No. 58-92537 discloses a variable damping force shock absorber. This known shock absorber comprises a pressure cylinder forming working chamber having first and second portions to store damping fluid. The absorber further comprises a first control valve for controlling the flow of damping fluid between the first and second portions of the working chamber during compression of the shock absorber. A second control valve is further provided for controlling the flow of damping fluid between the first and second portions of the working chamber during rebound of the shock absorber. A bypass passage has a port opening to the first portion and a valve port opening to the second portion. An externally controllable valve is provided to open or close the valve port. This externally controllable valve is adjusted to selectively change the damping characteristics of the shock absorber. The damping characteristics of this known shock absorber are not satisfactory since there is a point of inflection if a damping force characteristic curve is drawn.
An object of the present invention is to provide a variable damping force shock absorber which provides the damping characteristics without any point of inflection nor at least any noticeable point of inflection.